Explanation:

We can say that work is a form of inert energy. But we should not say that there is no difference between inert energy and work. If there is no difference between inert energy and work, what is the necessity of introducing a new word, work? Work must be different from inert energy and therefore, a new word, work, was created. If you say that there is no difference between inert energy and work, there should have been no work other than inert energy.